cannot write to c drive on windows 7 pro

all of a sudden a windows 7 pro user cannot write any type file to the c drive. This is a pc that has been running for 3 or 4 years. the error message says 'A required privilege is not held by the client'.
Tried setting all the users with full access. We changed the permissions of the EnableUA to be '0' in the registry. None of these helped.
Any ideas?
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JohnBusiness Consultant (Owner)Commented:
Run TDS Killer to check first for root kit viruses and repair these.

Run System File Checker first.  Open cmd.exe with Run as Administrator and run SFC /SCANNOW. Allow to complete, shut down, start up and test.

If SFC does not repair the damage, run Windows 7 Repair Install.  For this, you need a working recovery partition or the Windows 7 DVD. Here is a Seven Forums tutorial to assist you.

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No user should be able to write to the root of C:\ or to any other system reserved directories. He should normally only be able to write into directories within his profile or the public folder, both within the \Users\ Folder. So what you are seeing is absolutely normal. If he was previously able to write directly into C:\ something was wrong then, or he was using an account with admin rights. No user should use a PC as Admin, the admin account should only be used for very special reasons, and if possible via UAC, and not logged on directly as it.
JohnBusiness Consultant (Owner)Commented:
I can make a folder in root of c:  (say C:\General Storage) and write to it without special permissions. You may not agree with my approach, but so long as the folder is not in Windows or Program Files, you should be able to write to it.

in this case, it was the change that makes me think something has gone wrong.
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I can also create a directory, but I can't write any files directly into C:\. Not with a standard user account.
dsi8dsiAuthor Commented:
This user was an admin and had been writing to the C: drive for years.  We are thinking he did a Windows Update this week, and now those permissions are gone.  All of our other Admin users have been writing to C: for years and none of us have run into this problem before.   All of the reports in our software package write the PDF report to the C: and then the user can choose to print it, email it, or save it to another directory.  This is the first time any user has reported a problem.
JohnBusiness Consultant (Owner)Commented:
Recent updates have had no impact on permissions on a machine that is working properly. As noted, check for viruses and root kit viruses.
dsi8dsiAuthor Commented:
John, we ran the TDS Killer and it came up clean.  When we try to run SFC, it gives us the message "Must be an administrator running a console session to use the SFC utility."  I have someone trying to figure out how to get around that setback now.
JohnBusiness Consultant (Owner)Commented:
On this machine, log out, and log in as an administrator - either local admin or server admin. Then run SFC again. It should run, and if not, something has compromised the machine.
It is still wrong for anyone to be allowed to write into the root of C:\, and allow users to logon as an Admin as a standard course of action. You can give him the password to an Admin account if necessary, but that must only be used when absolutely necessary. Even I who am the Admin and only user of my PC's login as a standard user. I also don't see any reason why a file has to be saved into the root of C:\. You can save it elsewhere, and also print it from there. If your software saves it to C:\ then it isn't setup properly or working as it should. But of course that is my point of view my point of view (and that of normal admins).
You don't need to logon as an admin to run sfc /scannow, just open a CMD prompt with admin privileges (right click on cmd.exe and select "Run as Administrator").
dsi8dsiAuthor Commented:
rindi,  If I was running a traditional network, I couldn't agree with you more.  Our sales force are "independent" contractors that are required to purchase their own computers and in many cases work out of their homes.  (So most are configured as Admin) The legacy software we use writes to the C: and then the user is free to move the PDF reports on their machine.   In 17 years, this is the first time we have had a machine stop letting us write to the C:.  I don't want to argue the merits of how we do it, but I am just supposed to fix it.  I am sure you understand.
dsi8dsiAuthor Commented:
Ok, we ran the sfc as administrator, and now it states:
Windows Resource Protection found corrupt files but was unable to fix some of them.  Details included in CBS.log

We can see the log file, but we can't open it or copy due to "invalid privileges" since we are "not" an administrator.  Thanks for all of your help on a busy Friday for a guy who can't seem to help himself.
This sounds like a disk problem. First run the disk manufacturer's diagnostic tool on it. You'll find it on the UBCD:

If it finds unrepairable issues on the disk, replace it. If the disk is fine, run a chkdsk /f /r on all it's drive letters, also from an elevated CMD prompt. It that finishes successfully, run the SFC /scannow again.
JohnBusiness Consultant (Owner)Commented:
Also, try running Windows Repair Install as suggested earlier. Support thread back there as well.
dsi8dsiAuthor Commented:

Even though we could not read the CBS.log file, the user rebooted his computer.  When his computer came back up, he can now write to the C: again.  (whether that is right or wrong).  

Thank you John and rindi for sticking with me today.
dsi8dsiAuthor Commented:
I am really new to this stuff but John Hurst and rindi were awesome!!
JohnBusiness Consultant (Owner)Commented:
@dsi8dsi  - You are very welcome and I was happy to help.
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